Tested all avalable amd64 kernels in Dapper: 2.6.15.23, 2.6.15-25, 2.6.15-26. None of them will show the second PCIe card (of course it doesn't matter what nvidia driver I have if the device does not show). NVIDIA engineers suggest compiling a new kernel... not an option in Dapper. As a reference, Mandriva kernel 2.6.12-12mdksmp can detect it. Maybe the PCI bridges detction is wrong..?
This is the output of lspci. There's supposed to be another identical "VGA" card at 0000:81:00.0.
0000:00:00.0 Memory controller: nVidia Corporation CK804 Memory Controller (rev a3)
0000:00:01.0 ISA bridge: nVidia Corporation CK804 ISA Bridge (rev a3)
0000:00:01.1 SMBus: nVidia Corporation CK804 SMBus (rev a2)
0000:00:02.0 USB Controller: nVidia Corporation CK804 USB Controller (rev a2)
0000:00:02.1 USB Controller: nVidia Corporation CK804 USB Controller (rev a3)
0000:00:04.0 Multimedia audio controller: nVidia Corporation CK804 AC'97 Audio Controller (rev a2)
0000:00:06.0 IDE interface: nVidia Corporation CK804 IDE (rev f2)
0000:00:07.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
0000:00:08.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
0000:00:09.0 PCI bridge: nVidia Corporation CK804 PCI Bridge (rev a2)
0000:00:0a.0 Bridge: nVidia Corporation CK804 Ethernet Controller (rev a3)
0000:00:0e.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
0000:00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
0000:00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
0000:00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
0000:00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
0000:00:19.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
0000:00:19.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
0000:00:19.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
0000:00:19.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
0000:05:05.0 FireWire (IEEE 1394): Texas Instruments TSB43AB22/A IEEE-1394a-2000 Controller (PHY/Link)
0000:0a:00.0 VGA compatible controller: nVidia Corporation: Unknown device 009d (rev a1)
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